It is already known to provide amphibious vehicles with steering systems capable of operation on land and water. Most simply, these systems are composed of two independent steering arrangements, for example, a steering wheel which is connected to a conventional rack and pinion arrangement for land operation, and a tiller, which is connected to the head of a rudder for water operation.
In more advanced steering systems, a steering wheel controls both land steering and water steering. For example, in U.S. Pat. No. 5,727,494, an amphibious vehicle is disclosed having a steering wheel connected to a fixed gear box by means of a shaft. The fixed gearbox is telescopically connected to a moving gear box, and steering rods connected to the moving gear box enable turning of the front wheels of the vehicle. The steering shaft is also connected to a mechanical cable steering system which controls turning of a rudder. The land and water steering arrangements are both permanently connected to the steering wheel. It is considered that known cable steering systems are inflexible in their relation of force to distance. Movement of the marine steering system may be undesirable in road mode.